Abstract SC2 Scientific Core 2 expresses proteins that are essential for the three Projects of the PPG. The proteins are expressed primarily in bacteria and also insect cells. The proteins are then purified and characterized to test that they are properly folded and functionally active. SC2 also constructs vectors for expression of proteins in mammalian cells. Sequences of all constructs are verified. These high-quality reagents are then turned over to the projects for utilization in proposed experiments. Over 50 proteins and 50 DNA vectors will be constructed in the Core. By centralizing these activities, common reagents and expertise can be shared and consistent behavior of shared reagents and outcomes can be assured. Scientific Core 2 also provides training to PPG personnel in to protein expression in bacteria and mammalian cells, protein purification and characterization and in mutagenesis strategies.